1. Technical Field
The present invention relates to a computer graphics technology, more specifically to multi-grid apparatus and method using a V cycle.
2. Background Art
Today's computer graphics (CG) technology has been widely utilized in various fields, including movies, animation and advertisement, with a proportionally increasing importance. Particularly, rendering fluids, such as water, fire, etc., which are major CG-utilized special effects, is a significant portion in the production of visual works.
The CG technology related to the rendering of fluids is mainly realized through scene representation, simulation, reconstruction and rendering processes.
The scene representation process is for reconstructing a fluid, which is an object of simulation, as well as an external object interacting with the fluid to forms that are appropriate for simulation.
While it is imperative that the interacting object be rendered in a grid form as well in order to perform the simulation at a location of uniform grid, the initial conditions or boundary conditions, which are configured prior to the simulation, are configured during the scene representation process.
The scene representation process is also for configuring the initial conditions or boundary conditions of the simulation which renders the interacting object in a grid form.
The simulation process is for calculating the movement of the fluid with an equation such as the Navier-Stokes equation for describing a movement of the fluid or a random factor.
In the reconstruction process, an external appearance is calculated from a simulation result of the fluid, such as water, having and maintaining an external appearance, by calculating the external appearance from arbitrary points or updating the initially calculated external appearance.
In the rendering process, a final image is created from a relation between light and the fluid configured in the form of a point, a face or an arbitrary function.
Among the processes described above, the simulation process takes up the most amount of time because a very large amount of calculation needs to be carried out in the simulation process.
The simulation process of a fluid involves obtaining a solution of the Poisson equation. Mainly used for obtaining the solution of the Poisson equation is the conjugate gradient method, the preconditioned conjugate gradient method or the multi-grid method.
The multi-grid method has a fast calculation speed and has a relatively small amount of calculation time increased, compared to the other methods, despite an increased resolution of the simulation. Particularly, the multi-grid method using a V cycle is most popularly used for simulating a fluid.
The processes of the conventional multi-grid method using a V cycle are divided into and processed by the plurality of processors. Accordingly, the conventional multi-grid method using a V cycle is not a truly parallel processing method, in which the plurality of processors should be simultaneously used, and still requires an excessive calculation time to obtain a solution of a specific accuracy, thereby making it difficult to render the fluid realistically.